Display Pad Layout That Prevents Side Wiring Galvanic Corrosion
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Solution Overview
Problem
The challenge in display device manufacturing is the prevention of corrosion in side wiring, particularly due to galvanic corrosion between metals with different standard reduction potentials, which affects the reliability and longevity of the display.
Innovation Solution
The implementation of a side wiring configuration on a display device where the side wiring overlaps a specific region of the top surface pad that does not contact the top surface connection line, preventing direct contact with metals having different standard reduction potentials, thereby avoiding galvanic corrosion. This configuration includes a stepped portion for the first region in contact with the top surface connection line and a flat profile in the second region, using materials like silver for the side wiring and aluminum for the pad electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the side wiring is positioned to overlap with the top surface pad region that contacts the top surface connection line, then electrical connection is achieved, but galvanic corrosion occurs between metals with different standard reduction potentials
Solution Approach 1:
The top surface pad is divided into two distinct regions: a first region that contacts the top surface connection line and a second region that does not contact the connection line. The side wiring is positioned to overlap only with the second region, thereby segmenting the pad structure to prevent direct contact between dissimilar metals and eliminate galvanic corrosion while maintaining electrical connection functionality.
Solution Approach 2:
The interlayer insulating layer serves as an intermediary barrier between the top surface connection line and the top surface pad. This insulating layer prevents direct contact between metals with different standard reduction potentials, thereby eliminating galvanic corrosion while allowing electrical connection to be established through the structured overlap in the second region.
2Ease of manufacture
If the top surface pad has a uniform flat profile, then manufacturing is simplified, but the side wiring cannot be properly positioned to prevent corrosion
Solution Approach 1:
The top surface pad is designed with different local qualities: the first region has a stepped profile to accommodate contact with the top surface connection line, while the second region has a flat profile to allow proper positioning of the side wiring. This local differentiation enables both manufacturing feasibility and corrosion prevention functionality to be achieved simultaneously.
Solution Approach 2:
The pad structure transitions from a two-dimensional flat profile to a three-dimensional stepped profile in the first region, creating vertical differentiation. This dimensional change allows the pad to accommodate both the connection line contact requirement and the side wiring positioning requirement for corrosion prevention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively prevents corrosion of the side wiring, ensuring reliable electrical connections and extending the lifespan of the display device by isolating metals with different reduction potentials, thus maintaining the integrity of the electrical pathways.
Implementation Method 1
prevention of corrosion in side wiring, particularly due to galvanic corrosion between metals with different standard reduction potentials
Data Source
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AI summary
A display device includes, a substrate including a first surface and a second surface opposite to the first surface; a light emitting element on the first surface of the substrate; a top surface pad on the first surface of the substrate and spaced from the light emitting element; a driving circuit on the second surface of the substrate to apply a driving signal for driving the light emitting element; a top surface connection line between the first surface of the substrate and the top surface pad to electrically connect the top surface pad to the light emitting element; an interlayer insulating layer between the top surface connection line and the top surface pad; and a side wiring on the top surface pad to connect the top surface pad to the driving circuit.